Application fields of various power conversion devices have been developed as variable voltage/variable frequency inverters are put to practical use.
With regard to power conversion devices, development of an application technique of a step-up/step-down converter has been widely in progress. Along with this development, in recent years, development of wide bandgap semiconductors has been widely in progress. The wide bandgap semiconductor has characteristics such as a higher voltage resistance, a lower power loss, and being capable of operating under a higher temperature, as compared with conventional semiconductors, and thus has been put to practical use mainly in rectifiers with regard to an element having a small current capacity (see, for example, Patent Literatures 1 to 4).